Several previous postings to these pages have shown birds
that have undergone more extensive moults than normal. There are some
individuals at the other end of the range, having renewed very few feathers in
their post-juvenile moult. A Greenfinch Carduelis chloris ringed on 13 October 2004
was unusually late in its moult and was aged as a Euring 3J (a first-year bird
still with some juvenile feathers). It is still moulting from
its juvenile plumage, having some juvenile (streaked) breast and neck feathers:

On its wings it looks as if it
is retaining all of its juvenile greater coverts, carpal covert and alula, and
is actively moulting just one median covert, the feather emerging from its
sheath just to the right of my thumb in the picture below. This is
a very un-extensive degree of post-juvenile moult and probably explained by the
late date:

Similarly, a Song Thrush Turdus philomelos ringed on
28 November 2004 was an unusual bird, a first-year with entirely
juvenile greater coverts and its moult limit half-way through its median coverts.
Apologies that the photograph (below) is not very high quality because it was
taken indoors with flash,
the bird having been caught at dusk coming into roost.

Jenni and Winkler (Moult and Ageing of European
Passerines, Academic Press, 1994) give figures for their sample
of 1103 Song Thrushes ringed in Switzerland, of which 0.8% had not moulted any greater coverts.
But Jenni & Winkler state that median coverts are 'usually all moulted ... (but) birds with no
greater covert moulted may retain individual juvenile median coverts': the
bird shown above is unusual in having retained so many juvenile median
coverts.

Another Song Thrush with an
identical moult pattern was caught on 19 December 2004 at the same site, and could have been a sibling.
I suspect that these are late-hatched birds from a species with a very extended
breeding season. Jenni & Winkler show (their Fig. 289) a reduction in the mean
number of moulted greater coverts as the migration season goes on, presumably
backing up the point about later-hatched birds having less extensive moult.

In another example of how some features of birds' biology can
translate across thousands of miles, the limited moult of these Song Thrushes is
almost identical to that exhibited by one of their close relatives, the American Robin Turdus migratorius
caught on 10 November 2004 by my good friends at Powdermill Nature
Reserve, Pennsylvania, USA, and depicted on their
website.

A seasonal tone to this Christmas/ New Year page is brought by
a Mistle Thrush Turdus viscivorus, whose common name and scientific name
both come from its longstanding habit of
eating berries of Mistletoe Viscum album. Nowadays, however, they are much more likely to be
found defending a large bush of holly Ilex aquifolium.

This bird was a first-year, Euring age code 3, shown by its
moult limit in the greater coverts, with four 'old' (juvenile) feathers.

Not many of us in Britain gain familiarity with ageing Mistle
Thrushes, as relatively few are ringed - only around one-hundredth of the
numbers of the commonest thrush, the Blackbird Turdus merula - but, as well as the difference in colour and texture between the two
generations of feathers in the greater coverts, there is also the obvious step in size, usually found with thrushes.
We should, however, beware of oddities such as the Robin Erithacus rubecula
shown below. Both the step in size from the innermost four greater coverts to
the outermost six, and the lighter-coloured spots on the
tips of three of the outermost greater coverts, could fool the unwary ringer into thinking this is a
first-year bird but in fact it was ringed two years ago. As pointed out
previously, it is
certainly not true that the presence of any buff tips has to indicate a first-year Robin.
The buffish shaft on the outermost median covert might also have been designed
to mislead us! But the colour and texture (glossiness) of the greater coverts is
the same, and I guess that the step in size just has to be explained-away as an
oddity.

This website is not supposed to be a 'freak show', but some
strange plumages demand attention and comment. The Great Spotted Woodpecker Dendrocopos major shown
previously just over a year ago (18
December 2003) was retrapped in my garden on 11 December 2004, and has still not moulted some of its feathers, although others have
been renewed normally.

Hatched in 2002 or earlier, this bird is now at least
two-and-a-half years old, and in its annual moult in 2004, as in 2003, it missed
replacing many of its feathers, which are now bleached and pale, but still serviceable!
The old feathers on top of its head give it a distinctly odd look:

On the other hand, it has moulted a new tail,
some primaries and some secondary feathers.
Comparison with photographs from December 2003, and the detailed moult card
completed then, shows that most of the secondary feathers were not moulted
normally in 2003 and thus are now at least two-and-a-half years old, and clearly
appear to be very bleached, although not badly worn. The image is annotated with
the year in which the secondary feathers were grown; the
contrast between the generations of feathers is striking:

One would have thought that a bird looking like this must be
in trouble, with some physiological malfunctions, but it has clearly survived to
a reasonable age. It might also be expected to be in poor condition, so what about the traditional measure
of condition, the bird's weight? Who would have guessed that its weight was
identical, to within 0.1g, to when it was first ringed a year ago, and that this
is actually the heaviest Great Spotted Woodpecker
(87.8g) that I have ever measured in 25 years of ringing?